Mixtures of azo dyestuffs



Patented Sept. ll, 1945 UNITED STATES. f PATENT OFFICE lihXTURES or AZO nms'rUFF's Friedrich Felix and Alphonse Heckendorn, Basel,

Switzerland, assignors to the firm Society of Chemical Industry in Basic, Basel, Switzerland- No Drawing. Application September 11, "1943, Serial No. 502,027. In Switzerland October 2,

Claims (01. 8- 26) I v become known that the acid sulfuric acid esters of the para-aminoazo-dyestufls which correspond to the type 1 elkylene-O-BOaH R1- N=N--Rr-N alkyl V wherein R1 and R2 stand mostly also for benzene nuclei, can be used successfully for dyeing cellulose esters, especially acetate rayon. Recently, quite a series of azc-dyestufl's for cellulose esters and ethers have become known which all correspond to the just indicated type.

However, the manufacture of such dyestuffs requires the production of unsymmetrical-N-dialkylated aromatic amines, which entails the manufacture of pure N-monoalkylated amines. thus making a special operation necessary. In many cases, however, no requirement exists for the symmetrical N-dialkylated amines which are always formed thereby. When trying to circumvent this complication by producing and using,

It has now been found that the para-aminoazo-dyestufis of the general formula I alkylene-OH R|N'=NRr alkylene-OH wherein R1 and Rn have the above given significance, R1 carrying 9. nitro group in para-position to the N=N- group and R: carrying the N== N- group and the a A g atom inparaposition to one another. which dyestuffs have been partially converted into acid sulfuric acid esters, are products which,

especially in the form of their salts, for example in the form of their alkali or ammonium salts, are distinguished from the non-esterifleddyestufls by their good solubility in water and from the completely esterifled products by their excellent afilnity for cellulose esters and ethers.

- They dye these textile materials, according to respectively. para- -aminoazo-dyestufls of the type I (wherein R1 and R2 have the above given signincanoe). it is found that such dyestufls are not suitable for dyeing acetate rayon, as they have a much too weak afllnity fcr'such materials when dyed from their aqueous solutions.

their constitution, preferably red to brown, violet and blue shades. The new dyestuffs may also be used for other purposes, for example for dyeing synthetic fibers of animal character, such as superpolyamides or superpolyurethanes.

For producing the new products one may start it quite generally from primary aromatic amines of the general formula I I alky1cne-OH alkylene-OH wherein R represents an aromatic nucleus of the benzene series which is capable of coupling with dlazo compounds in 4-position to the Y I I alkyione-QH f m n alk'ylene0H Y and from unsulfonated diazo compounds of the benzene series nitrated in 4-position to the diazo group, the

omen -on zw p elkylene-OH either before or after coupling to the azo-dyestuil. being converted with suitable esterifying agents,

such as sulfuric acid, chlorosulfonic acid, etc.. into 4-nitrobenzene,

f-N=N and the an acid sulfuric acid ester in such a manner, that at least one, but not both OH-groups are esteri= fled. It has been found, that the esterification may be effected in a surprising manner in stages, the most favorable conditions regarding afinity and solubility being different depending on the nature of the azo-dyestuff. Whereas, for example, certain azo-dyestuifs behave best in the form of their monoesters, a higher degree of esterification is appropriate in other products, so that for example up to 1 OH-groups must be esterified.

The new dyestuifs are therefore derived from preferably symmetrical N-dihydroxyalkylated aromatic amines, such as N-di-hydroxyethylaminobenzene, 3-methy1 N di-hydroxyethylaminobenzene, 3-chlor0 N di-hydroxyethylaminobenzene, 3-methom -N-di-hydroxyethylaminobenzene, Z-methoxy- N -di-hydroxyethylaminobenzene, 2-methoxy 5 methyl-N-di-hydroxyethyl-aminobenzene, 2:5-dimethoxy= or 2:5-diethoxy-N-di-hydroxyethyl aminobenzene,

2:o-dichloro-i-nitrobenzene, l-amino-ZM-dinitro-6-chlorobenzene, i-amino-E-cyano--hitrobenzene, 1-amino-2-cyano-fi-chloroi-nitrobenzene, 1-amino-2-cyano-4:fi=dinitrobenzene, 1- amino 2 methylsulfone e nitrobenzene, 1- amino-2-methylsulfone-4 fi-dinitrobe nzene, and

the like. I a

The new products represent therefore mixtures of dyestufis which. in the free form correspond to the general formulas alkylen'e-O-SOaH wherein the proportion of the monoester (I) to .the diester (11) is such that in 100 parts of dyestuff mixture the content of monoester (1) amounts to at least 50 per cent. and the content of dieste'r (II) amounts to not more than per cent., in which formulas R1 and R2 stand for aromatic nuclei of the benzene series which are free from hydroxyl, carboxyl and sulfonic acid groups, R1 containing a nitro group standing in para-position to the --N=N group, and the alkylene I alkylene groups in R2 standing in 1:4-positlon to each other.

The following examples illustrate the invention, but are not to be regarded as limiting it in any way. the parts being by weight:

- the presence of ice.

ascazea Example 1 195 parts of S-methyl-N-di-hydroxyethylaminobenzene are dissolved in'1000 parts by vol ume of carbon tetrachloride while slightly heating to ail-45C. To this solution are gradually added 116-150 parts of chloros'ulfonic acid from I a dropping funnel, while stirring the solution, the

operation being conducted in a reflux apparatus.

The reaction occurs instantaneously with evolu tion of gaseous hydrochloric acid and heat. As theesterification advances, the reaction product is precipitated as a viscous mass from the carbon tetrachloride solution. When the whole quantity of the chlorosulfonic acid is introduced, the solution is allowed to cool, while stirring, the mixture which can now be stirred only with difficulty isv mixed with 2000 parts of warm water and stirring is continued until all is dissolved. The aqueous solution of the ester is thensepar'ated from the carbon tetrachloride in a separating funnel and coupling is effected by allowing the diazo solution obtained as described below from l-amin -2- cyano-i-nitrobenzene to flow to the solution in The diazo solution is ob tained by introducing '70 partsof sodium nitrite into 1000 parts of concentrated sulfuric acid and then 163 parts of 1-amino-2-cyano-4-nitrobenzene into the nitrosyl sulfuric acid thus obtained. When coupling is complete, the mineral acid in excess is made neutral to congoby addition oi about 1300 parts of sodium hydroxide solution of 30 per cent. strength and the dyestufi suspension is neutralized completely with some ammonia. The dyestuif is salted out by addition of common salt, suction-filtered and washed with a dilute common salt solution. After drying there is obtained a dark powder which dissolves readily in water and dyes acetate rayon from the neutral bath in the presence oi sodium sulfate 'violet shades. A similar dyestufi which dyes acetate rayon red-brown shades is obtained when using in this example as cliazo componentZO? parts of Lamina-2 o-dichloro-e-nitrobenzene.

w Example 2 The operation is conducted as in Example 1.. -When the esterification of the 3-methyl-N-dihydroxyethyl-aminobenzene with chlorosulicnic acid is complete and after cooling the mixture, the carbon tetrachloride in excess is decanted and remains which are still adhering to the mass are removed in a vacuum. The residue thus obtained is then dissolved in 3000 parts by volume of methanol, the solution is cooled to 10 C. by external cooling and coupled by adding the diam solution from 1-amino-2-cyano-4:G-dimtrobenzene drop-by drop. The diazo solution is obtained by introducing 70 parts of sodium nitrite in 1000 parts of concentrated sulfuric acid and then 208 parts of l-amino-Z-cyano-4:G-dinitrobenzene into the nitrosyl sulfuric acid thus obtained. When coupling is complete, the methylalcohclic dyestufi suspension is poured into ice'water, the dyestufi is suction-filtered, stirred with a little water, neutralized with ammonia and sucked ofi. When dry there is obtained a dark powder which dissolves readily in water and dyes acetate rayon from the neutral bath in the presence of sodium sulfate blue shades.-

Example 3 12.3 parts of chlorosulfonic acid are gradually introduced into the solution of. 33 parts of the water-insoluble azo-dyestufl which is obtained by coupling N- di-hydroxyethyl-aminobenzene with the dim compound or l-amino-4-nitrobenzcne, in 200 .parts by volume of tetra-chloroethane,

. while heating and thoroughly stirring, the temthe above prescriptions-if necessary modified appropriately-from the diazotizir'ig and coupling components mentioned in the introduction. From the following list can be gathered the composition oi such dyestufls as well as the shade of the dyeings which they yield on acetate rayon:

Example 4 1 part of the dyestufl of the first paragraph of Example 1 is dissolved in 3000 parts of water. The dye-bath is mixed with parts of crystallized sodium sulfate and 100 parts of acetate rayon yarn are treated in this bath for 1 hour at 0.. After rinsing and drying there is obtained an acetate rayon which is dyed pure violet shades.

Example '5 1.2 parts of the dyestufi of Example 2 are dissolved in 3000 parts of water, the dye-bath is mixed with 40 parts of crystallized sodium sulfate, and parts of a superpolyamide yarn (which is on the market under the registered name "Nylon) are dyed in this bath for 1 hour at 80-90 C. After rinsing and drying an extensively blue colored fiber is obtained.

carom-0H (Esterified with 1.1 mole. eulfoneting agent Scarlet. [NHe-Bolfl). (1) NO: N=N N\ CHr-CHr-OH v CH,CH,OH (Esterified with 1.2 mole. sulfonating agent Red.

[Ne-saith. (2) N0 N=N CHr-CHr-OH CH3 CH2CH:OH (Esterified with 1 mo]. sullonating agent Ruby red. [K-saltl). (a) N0 N=N N\ l CHr-CHz-0H Oi (Esterified with 1 mol. chlorosullonio aold brown.

7 CHr-CHr-OH [NIL-said).

(4) NO N=N CHr-CHr-OH 1 Hi v CHz-CH1-0H (Esterlfied with 1 mol. chlorosullonic acid Red violet.

[NHt-saltl). (0) N0 N: N\

CH1CH:OH N Ha v Cl (Esterified with 1.3 mols. sulfonating agent Violet.

CHr-CHz-OH {Na-saith.

(6) N0 N=N N CHs-CHrOH N Ha N0, (Esterified with 1.25 mole. chlorosulionic acid Bluew /CE:-CH:OH [NHrSEiltD- 1 N0 N=N N\ carom-0n N HI I No, 0cm (Esterifled with 1.2 mole. slillonating agent Greenish blue. CHPCHr-CHr-OH [Na-saltl). f (8) N0 N: N\

' CHrCHrCHr-OH N NH-CO-CH:

CH; (Esterified with 1.2 mole. sulloneting agent Ruby red". 01 3)- H-CHr-CHa-OH CH-CHr-CHr-0H Cl (Estarified with 1.2 mole. suL'onating agent Do. /CHr-CHa-OH [Na-saltl). (10) NO N'='N -N CH-CHa-CHg-OH What we claim is: 1. The mixtures of dyestufiswhich in the free form correspond to the general formulas ulkyIene-O-SOaH wherein the proportion of the menoester (I) to the diester (IE) is such that in 1% parts of dye= stufi mixture the content of monoester (I) amounts to at least to ear cent. and. the content of die-star (II) amounts to at the most 25 per cent, in which formulas R1 and R2 stand for aromatic nuclei of the benzene series which are free from hydroxyl, carboxyl and sulfonic acid groups, R1. containing a nitro group standing in para-=position to the N=N group, and the =N=N-= and the N/alkylenF nlkylenegroups in R2 standing in lz-position to eac other, the term alkylene'in the foregoing formulae signifying an alkylene containing not more than 4 carbon atoms.

2. The mixtures of dyestuffs which in the free form correspond to the general formulas wherein the proportion of the monoester (I) to the diester (H) is such that in 100 parts of dyestufi mixture the content of monoester (I) amounts to at least 50 per cent. and the content of diester (II) amounts to at the most 25 per cent,

in which formulas R1 and R2 stand for aromatic nuclei of the benzene series which are free from 50 3. The mixtures of dyestufis which in the free form correspond to the general formulas and ' CHr-CHPO-BOAH N0 N: (11 em CHz-CHrO-B wherein the nroportion of the monoester (I) to the diester (H) is such that in 100 parts of dyestufi mixture the content of moncester amounts to at least so per cent. and the content of diester (II) amounts to at the most 25 per cent 4. The mixtures of dyestuffs which in. the free form correspond to the general formulas CHrCHrO-SOtH CN NoQm N( I I (n) m-cm-o-sou:

No, in

wherein the proportion of the monoester (I) to the diester (II) is such that in 100 parts of dyestufl mixture the content of monoester (I) amounts to at least 50 per cent. and the content of diester (II) amounts to at the most 25 per cent.

- 5. The mixtures of dyestufis which in the free form correspond to the general formulas cm-om-o-sodi wherein the proportion of the monoester (I) to the diester (II) is such that in 100 parts of dyestufl mixture the content of monoester (I) amounts to at least to per cent. and the content of diester (II) amounts to at the most 25 er cent.

FRIEDRICH FELIX. ALPHONSE 

